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vuln-cve/data/2026/89xxx/CVE-2026-89667.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-89667",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-09-11T19:38:34.745Z",
"datePublished": "2026-09-11T19:45:53.609Z",
"dateUpdated": "2026-10-19T08:50:40.641Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-10-19T08:50:40.641Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache\n\nThe shrinker, GC worker, and fsnotify/lease callbacks can unhash an\nnfsd_file from the rhashtable and then call\nnfsd_file_dispose_list_delayed() to move it to the per-net dispose list.\nIf nfsd_file_cache_shutdown_net() runs concurrently, its rhashtable walk\nmisses the already-unhashed file, and its drain of the per-net dispose\nlist can run before the file has been queued. The file then sits on\nthe per-net list with no thread to drain it, leaking both the file and\nits associated state.\n\nThe GC worker and shrinker already hold nfsd_gc_lock while walking the\nLRU, but in the original code they release it before calling\nnfsd_file_dispose_list_delayed(). The fsnotify/lease path\n(nfsd_file_close_inode) has no synchronization at all.\n\nFix this by:\n\n 1. Widening nfsd_gc_lock in both nfsd_file_gc() and nfsd_file_lru_scan()\n to cover the nfsd_file_dispose_list_delayed() call.\n\n 2. Wrapping nfsd_file_close_inode() in nfsd_gc_lock so that all three\n callers of nfsd_file_dispose_list_delayed() hold the lock.\n\n 3. Adding a spin_lock/unlock(nfsd_gc_lock) barrier in\n nfsd_file_cache_shutdown_net() after the purge, so that any\n in-progress disposal has fully completed before the per-net list\n is drained.\n\nAll operations inside the lock are non-sleeping (rhashtable lookups,\natomic bit/refcount ops, list moves, svc_wake_up), so the spinlock is\nappropriate."
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 8.1,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The vulnerable nfsd filecache GC, shrinker, and fsnotify close paths run in the in-kernel NFS server and are reached by NFS RPCs (OPEN/READ/WRITE/REMOVE) on TCP/UDP 2049 from a remote client; no local login is required.\nAC:H - Hitting the bug requires nfsd_file_cache_shutdown_net() to interleave with unhash plus delayed dispose; a remote client can populate the cache and trigger GC, shrinker, or fsnotify close, but cannot itself stop nfsd or destroy the server net namespace.\nPR:N - Typical nfsd deployments allow AUTH_SYS/AUTH_NULL with IP-based exports, so a remote peer that can reach the export self-asserts credentials with no cryptographic authentication and can populate the filecache via READ/WRITE.\nUI:N - Attacker-sent NFS operations drive the filecache side; no victim user action such as mounting a filesystem or opening a local file is required.\nS:U - The use-after-free or leak corrupts kernel nfsd_file/nfsd_net state within the host nfsd authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Delayed dispose can call net_generic() and list_move on nfsd_net after per-net teardown frees it, a use-after-free of slab per-net data that enables reuse/spray and arbitrary kernel memory disclosure.\nI:H - The same freed nfsd_net is used for spin_lock and list_move_tail, a use-after-free write primitive that enables heap spraying, object corruption, and control-flow hijacking.\nA:H - Use-after-free of nfsd_net can oops or panic, and leaked nfsd_file objects permanently pin struct file/inode state so filesystem and netns teardown can hang, fully disrupting the NFS server host."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/nfsd/filecache.c"
],
"versions": [
{
"version": "ffb402596147ac583f3464ff5c48feb9423e3838",
"lessThan": "b15997b53b61c74fb4d083f7261d19f389ff854f",
"status": "affected",
"versionType": "git"
},
{
"version": "ffb402596147ac583f3464ff5c48feb9423e3838",
"lessThan": "6d6b9f6a75c3767250e9c23ace4e384ab8f7843e",
"status": "affected",
"versionType": "git"
},
{
"version": "ffb402596147ac583f3464ff5c48feb9423e3838",
"lessThan": "08af9593e2b472fd98c00faf1bf03bdbb7203477",
"status": "affected",
"versionType": "git"
},
{
"version": "ffb402596147ac583f3464ff5c48feb9423e3838",
"lessThan": "40162cfea79b9510380decfdd1795b754dc9f972",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/nfsd/filecache.c"
],
"versions": [
{
"version": "6.9",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.9",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.12.111",
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.51",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.2.4",
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.9",
"versionEndExcluding": "6.12.111"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.9",
"versionEndExcluding": "6.18.51"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.9",
"versionEndExcluding": "7.2.4"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.9",
"versionEndExcluding": "7.3"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/b15997b53b61c74fb4d083f7261d19f389ff854f"
},
{
"url": "https://git.kernel.org/stable/c/6d6b9f6a75c3767250e9c23ace4e384ab8f7843e"
},
{
"url": "https://git.kernel.org/stable/c/08af9593e2b472fd98c00faf1bf03bdbb7203477"
},
{
"url": "https://git.kernel.org/stable/c/40162cfea79b9510380decfdd1795b754dc9f972"
}
],
"title": "nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
}
}